1999 Longhorn Nautique Restoration Thread |
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rosconole
Gold Member Joined: May-10-2008 Location: United States Status: Offline Points: 758 |
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This is almost better than the GT 40 vs GT 40 P heads debate !!!!
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1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee
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79SNbrady
Senior Member Joined: June-26-2008 Location: athens, Tn Status: Offline Points: 229 |
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Thread is blowing up today! Going to have to adjust my notifications to something different besides instant. Had to scroll through my emails to find something else besides this thread.
What is your next big mile marker your expecting to hit? This thread is giving me the itch to get my 79SN going again with a 408! |
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"It's just water... not concrete or dirt... so just throw it"
-Parks Bonifay 1979 Ski Nautique - (stringer job completed summer 2012) 2007 236 Team - All White! |
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rosconole
Gold Member Joined: May-10-2008 Location: United States Status: Offline Points: 758 |
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Yes BBK can be a nightmare same goes for their mass air units, you couldn't pay me to run one , not only do they not make good power trying to get the IAC /Trottle position set properly can drive a man insane sometimes. I have run a 90MM accufab for 20+ years. good people and good product.
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1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee
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DHMcFadin
Senior Member Joined: May-27-2019 Location: Austin, Texas Status: Offline Points: 312 |
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Correct. Lower was port matched to the heads, upper was opened up and the throttle body inlet. We will see how it works out.
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DHMcFadin
Senior Member Joined: May-27-2019 Location: Austin, Texas Status: Offline Points: 312 |
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This is the throttle body:
https://accufabracing.com/mustang-throttle-bodies/mustang-1986-1993/5.0l-mustang-throttle-bodies/mustang-5.0l-1986-1993-70mm-throttle-body I didn’t know the BBK’s were problematic. Good to know.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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Only (some of?) the 1995 gt40 intakes are tubular. The rest (including his 99) are cast.
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rosconole
Gold Member Joined: May-10-2008 Location: United States Status: Offline Points: 758 |
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The lower is only part you can port on GT40 intake 9.2 deck lower...in he tubular upper really, you can tootsie roll the throttle body inlet some thats about it... some have tried to cut open and weld the side and change the runner some but not with alot of luck, not like the cast like Cobra or Explorer intake where you can extrude hone or port to your hearts desire. Hopefully its got an accufab throttle body and not the idle hunter BBK. GT40 intake should be fine for what your doing , Might benefit slightly from a Holley system max intake but is it worth another 800...maybe later. |
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1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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It’ll be close but I suspect you’ll be right there.
Prop selection is always a bit of trial and error but I bet you’d be darn close in the 1490-1492 range. |
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DHMcFadin
Senior Member Joined: May-27-2019 Location: Austin, Texas Status: Offline Points: 312 |
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Over 50 is the goal. We will see. Prop selection may be a little bit of trial and error. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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You’re 100hp shy on what it’d take to push that Sport hull 52... but I’d say the speed estimate is probably close. Which side of the intake is ported? A quick search shows that the 351w lower GT40 intake is pretty decent but the upper (same as the 302 Explorer?) is a bit more restrictive. 70mm TB will help. |
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DHMcFadin
Senior Member Joined: May-27-2019 Location: Austin, Texas Status: Offline Points: 312 |
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The only thing that is “original” is the intake and block (if you don’t count machine work). The PCM FCC system and fuel rails are also being reused but a much higher volume HP pump is being used within the FCC canister. Goal was to idle like stock and appear stock until you get into the drivers seat. |
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rosconole
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Sorry I thought it was staying more OEM But with those heads can't go wrong. it will probably make 330-340hp., 52mph.
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1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee
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DHMcFadin
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Intake was ported and now has a 70 mm throttle body.
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TRBenj
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Try to read it all Ross... he’s using AFR heads (185’s IIRC).
The intake may indeed be a restriction since this is a 351 stroker rather than a 302 more commonly seen in Mustangs. I’d do some more reading. There are aftermarket options that don’t look wildly different. |
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rosconole
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You get a cam card typically and thats it with the specs , usually after you specify certain paramaters you want and a certain rpm range your operating....the biggest restriction being able to benefit fully from a stroker combination in this case will be the throttle body 55mm I am guessing, lower intake unported and cylinder heads unported. |
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1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee
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rosconole
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WOW not only a prop expert !
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1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee
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TRBenj
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4” wont change much. Dual 3” out the back is fine (single 4” is about the same cross section). Your risers are 3.5”. It’s the individual runners in the manifold that aren’t huge relative to the exhaust ports... but otherwise the pcm pyramids are pretty decent. I don’t think the GT40 intake will be a significant bottleneck based on its relative popularity on the automotive side.
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DHMcFadin
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The only bottleneck could be the intake. Exhaust manifolds are now 4” manifolds. The engine that came out of the boat was a gt40. I am trying to reuse the gt40 intake for aesthetic purposes to keep the originality. If it doesn’t work out, I’ll go another route. I would be willing to sacrifice a little bit of power to keep the engine looking oem but if the power loss is too great, I’ll make a change. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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It’s going to make more power than that I suspect... unless there’s a massive bottleneck somewhere that you haven’t mentioned. Even breathing through stock exh manifolds, that cam and head combo with 408ci behind it should pull well past 5k. I’d guess 425 at 5400 if not more.
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DHMcFadin
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Expected is 380-400 hp and 460-480 ft lbs on 93 according to simulation. Can’t speculate any further until it’s dynoed.. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Or one of these is even better.
Wouldn't the cam supplier have an approximate graph? |
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Hollywood
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I see numbers
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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Not sure I quite buy that... no peak numbers?
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DHMcFadin
Senior Member Joined: May-27-2019 Location: Austin, Texas Status: Offline Points: 312 |
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Max HP 5000 rpm
Max TQ 3200-3400 rpm
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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Smh.
Cam choice seems reasonable. Did the builder have a hp @ rpm prediction? |
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rosconole
Gold Member Joined: May-10-2008 Location: United States Status: Offline Points: 758 |
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Just trying to save you from tearing it back down when it looks like may run into problems! I've made over 1000 hp with a small block ford so I have seen alot before the internet was invented.
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1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee
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DHMcFadin
Senior Member Joined: May-27-2019 Location: Austin, Texas Status: Offline Points: 312 |
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Fully hydraulic roller. Here is the cam. Smooth idle was extremely important to me.
http://www.compcams.com/xtreme-energy-computer-controlled-216-224-hydraulic-roller-cam-for-ford-5-0l.html#tab2.tab2
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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Don’t worry about Ross... he talks a big game but is clearly out of his element. If he knew his ass from his elbow he’d recognize your roller block by the machined threads in the valley. I don’t recall seeing your cam specs posted, but assume you’ll be going roller since parts are readily available for this lefty. Whether you use the factory roller provisions (spider retainer and dog bones plus factory style lifters) or aftermarket tie bar lifters is just a matter of money. None of the Ford marine engines came roller from ford even if the block was capable.
In regards to our disagreement on compression ratio, I don’t imagine that an argument over FACTS can last very long. Presumably he will type those magic words into google (“how to calculate compression ratio”) and come to the quick conclusion that since a longer stroke increases swept piston volume (ie increases displacement), that a correspondingly larger combustion volume must accompany it to keep the CR in check. You can do that by increasing chamber volume in the head or increasing piston dish (for a ford Windsor- other makes you can decrease the dome). All looks normal here and don’t doubt the calculated 9.5, which seem appropriate. |
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DHMcFadin
Senior Member Joined: May-27-2019 Location: Austin, Texas Status: Offline Points: 312 |
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Thank you for the feedback. You have officially eliminated any excitement I had for this engine. Appreciate it. |
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Air206
Grand Poobah Joined: September-28-2008 Location: Roanoke, VA Status: Offline Points: 3000 |
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I'm just happy they are fussin' at each other rather than you!
Amazing changes to the boat and trailer. Very thorough. Thanks for sharing. |
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